Personality traits and incidence of pre-dementia conditions: A systematic review of longitudinal studies with meta-analysis

Personality refers to relatively stable patterns of thoughts and behaviors. The objective of this study is to investigate whether FFM personality traits are associated with the risk of developing pre-dementia conditions. A systematic search was conducted using keywords and MeSH terms in three databases. Random-effects meta-analyses were performed separately for studies reporting Hazard Ratios and Odds Ratios. Subgroup analyses by follow-up duration and sex were used to explore heterogeneity, also were run a meta-regression using time as slope. 13 studies were included in the review and 9 in the meta-analysis. Participants' mean age ranged from 45.6 to 81.3 years; most samples were predominantly female. Follow-up ranged from 1.5 to 12 years. Neuroticism was associated with higher incidence of pre-dementia conditions (HR = 1.08, 95% CI: 1.02–1.15; I2 = 81.3), while conscientiousness and openness show an inverse association (HR = 0.92, 95% CI: 0.84–0.99; I2 = 94.5; and HR = 0.97, 95% CI: 0.94–0.99; I2 = 10.3, respectively). No significant associations were found for extraversion and agreeableness. Subgroup analyses reduced heterogeneity for neuroticism and confirmed its associations in studies with 6 or more years of follow-up. Meta-regression showed a significant trend suggesting that the length of follow-up relates to how personality traits track with risk profiles for these conditions over time. In conclusion, higher neuroticism is associated an increased incidence of pre-dementia conditions, whereas openness and consciousness are linked to lower risk. Despite substantial heterogeneity, these findings suggest that personality traits might represent a complementary factor to consider in future risk stratification frameworks.